Control mechanism for grinding machines



H. A. SILVEN CONTROL MECHANISM FOR GRINDING MACHINES Oct. 8, 1935.

Filed Aug. 15, 1954 2 Sheets-Sheet l C'Jruomlua Ham 'HERBERT A. Sim/ENWQ\W I 9% QQ JW Oct. 8, 1935. H. A. SILVEN CONTROL MECHANISM FORGRINDING MACHINES Filed A g. 13, 1934 :2 Sheets-Sheet 2 Patented Oct. 8,1935 UNITED, STATES PATENT orrics grinding machine.

Heretoiore, in the grinding of certain types oi! work requiring the useof a chuck or other work holding means, it has been necessary tor theoperator to manually locate the work holding member in a given positionso that the work piece may be inserted in operative relation therewith.These mechanisms have required the operator to manually turn the workholder or chuck or to jog the control lever to engage the clutch androtate the chuck to the predetermined loading position. Similarly, afterthe work piece has been finish ground, it is necessary for the operatorto again jog the control lever or manually turn the work holder tolocate the work holder in an upright or predetermined loading position.

A grinding machine of this typeis disclosed in the prior patent toSilven and Belden No. 1,837,342 dated December 22, 1931. This machine isparticularly adapted and intended for use in grinding of the oifsetcrankpins of a crankshaft. The work piece is clamped in place in twoopposed work holders or pot chucks and is then clamped rigidly in placeby a spring actuated toggle clamping mechanism which is released aftergrinding by means of a fluid pressure piston and cylinder on each end ofthe table. The opposed pot chucks are rigidly mounted on a pair ofopposed work rotating spindles which are synchronously rotated from acommon drive shaft below the work supporting table. A manually operablecontrol lever serves to actuate a clutch to start the work rotation whenmoved into one position, or when moved into the opposite position servesto disconnect the clutch and engage a brake to immediately andsimultaneously stop the rotation of the work spindies and chucks. Insuch a mechanism, provision is made so that the pot chucks cannot beopened, that is, the jaws released to unclamp the work unless the potchucks are in an upright position. In order for the chucks to be stoppedin an upright position, it is necessary for the operator by experienceto throw the manual control lever so as to stop the rotation of the workholders and work piece in the required position.

In production grinding, it has been found that it is not feasible forthe operator to readily stop the chuck in the desired position, and itis necessary for the operator to jog the manual control lever to turnthe pot chuck through a partial rotation to bring the chuck to therequired loading position.

CONTROL MECHANISM .FOR GRINDING MACHINES Herbert A. Silven, Worcester,Mam, nuignor to Norton Company, Worcester, Man, a corporation ofMassachusetts Application August 13. 1934, Serial No. 739,010 S U 10Claims. (01. 51-237) This invention relates to grinding machines, andmore particularly to a control device for a work gripping and rotatingmechanism of a The necessity ior manually positioning the work holder orchuck in a predetermined location for removal of the finish ground pieceand loading 01' a new piece has resulted in a considerable loss of timein the cycle oi operation, thereby im- 5 pairing the emciency of themachine.

It is the primary object of this invention to provide a work rotationcontrol mechanism which automatically stops the rotation of the workholder in a predetermined or upright position ior l0 loading andunloading.

It is another object 0! the present invention to provide a suitable workrotation control mechanism which permits stopping either a single heador a double head work drive when the work hold- 15 er or pot chuck arein any predetermined position.

It is a further object oi'this invention to provide asuitable'electrical control mechanism which stops the work rotation whenthe work holders 20 are in an upright position.

Other objects will be apparent from the foregoing disclosure. Oneembodiment of this invention has been illustrated in the drawings, inwhich like reference numerals indicate like parts: 25

Fig. 1 is a combined diagrammatic fragmen- 'tary perspective view andelectrical wiring diaa control mechanism for grinding machine or 40other machine tool for automatically stopping a mechanism, such as thework rotating mechanism, when the work holder is in a predeterminedposition. In a grinding machine, such as a double head crankpin grindingmachine, th 45 control mechanism is arranged to automatically stop thework holders or pot chucks in an upright position so that after thegrinding operation has been completed, the work holders or chucks are ina proper position for unclamping the 50 work without dropping the samefrom the work holder. An electrical control device is provided tocontrol the work rotating mechanism so that the work holder or supportmay be stopped in any predetermined position. 55

A machine illustrating one embodiment of this invention has been shownin the drawings. comprising a base |9 which carries a wheel slide II onthe usual V-way l2 and flat-way N for a transverse movement relative to'the base I. A work supporting table II is. mounted on the usual V-way l6and a flat-way II for a longitudinal movement relative to the base II toposition the work piece |3 in operative relation with a rotatablegrinding wheel II on the wheel slide The work supporting table II may bemoved longitudinally by any suitable traversing mechanism, such as, forexample, either a manually operable or a power actuated mechanism. Forthe sake of simplicity of illustration, a manually operable traversemechanism has been illustrated, comprising a hand wheel 23 mounted onthe outer end of a shaft 2| which is Journaled in bearings (not shown)in the base l9. The shaft 2| carries a gear 22 which meshes with a rackbar 23 depending from the work table II.

The grinding wheel slide may be fed transversely either toward or fromthe work piece by means of any well known feeding mechanism, eithermanual or power actuated, to cause the desired feeding movement of thegrinding wheel relative to the work. A manually operable feedingmechanism has been illustrated comprising a feed wheel 25 mounted on theouter end of a shaft 26 which is journaled in bearings (not shown) inthe base l9. The shaft 23 carries at its inner end a gear 21 meshingwith a gear 23 on the outer end of a shaft 23. The inner end of theshaft 29 is formed as a feed screw 39 meshing with a nut 3| dependingfrom the wheel slide II. It will be readily apparent from the foregoingdisclosure that the grinding wheel |3 may be fed either toward or fromthe work piece |3 to grind the same to the required extent, or may beseparated from the work piece by rotating the manually operable feedwheel 23 in the desired direction.

The work piece may be mounted on any suitable type of work holder, butfor the sake of illustration a crankshaft work holder or pot chuck hasbeen illustrated similar to that shown in the prior Patent No.1,837,342, in which the crankshaft I3 is supported in a work holder 33which is fixedly mounted on the outer end of a work rotating spindle 36.In grinding a crankshaft, opposed work heads 35 (Fig. 2) are provided,each of which is supported on opposed aligned work rotating spindles 36.The work holders 35 comprise a partial cylindrical supporting member 31which is preferably rigidly fixed to the work holder 35 and is adaptedto engage and support the end portion 33 of the crankshaft. A clampingjaw 39 is pivotally mounted on the head 35 and is provided with anadjustable clamping pin 49 which is opposed to the supporting member 31.A clamping mechanism is provided for actuating thejaw 39 to clamp andrelease the work before and after grinding. This mechanism has not beenillustrated in detail, since it is not a part of the present invention.Such a mechanism is illustrated and described in detail in the priorPatent No. 1,337,342, to which reference may be had for details ofdisclosure.

Each of the spindles 33 is rotated by a link chain 45 which engages asprocket 33 on the end of each spindle 36 and is driven by sprockets 31mounted on opposite ends of a drive shaft 43 which is journaled inbearings 39 in the table l5. The shaft 43 is provided with a sprocket IIwhich is driven by means of a link chain II from a sprocket 52 on aclutch shaft 53. The shaft 53 may be rotated by power from any suitablesource, such as from an overhead belt drive or from aself-containedmotor drive within the machine.

A shiitable clutch member 35 is slidably keyed to the shaft 53 and isarranged to be thrown towards the left (Figs. 1 and 2) into engagementwith a positively rotated, power driven clutch member 56 to rotate theshaft 53 and the sprocket so as to drive to the parts above mentioned torotate the work holders 35. The clutch member 55 is moved toward theright (Figs. 1 and 2) to engage a stationary fixed brake member 53 so asto immediately stop the rotation of the shaft 53 and work holders 35.

The clutch member'55 is arranged to be shifted by a yoked member 69which is pivotally mounted on a stud 6|. The yoked member 69 isconnected by a link 62, a pin 63, an elongated slot 63, a pin 65 on arock arm 66. The arm 66 is fixedly mounted on a shaft 61 which isarranged to be rocked by a manually operable control lever 19.

In the position of parts as illustrated in Fig. '1, the clutch member 55is in engagement with the brake member 53, and the work spindles areheld against rotation. When it is desired to start the work rotation,the control lever 19 is moved toward the left, as viewed in Fig. 1, sothat the lever I9 moves into a notch 1| in a plate 12. This movementshifts the clutch member 55 from engagement with brake member 53 intoengagement with the clutch member 56 to start the rotation of thesprocket 52, link chain 5|, sprockets l3, shaft 43, sprockets 41, linkchains 45 and sprockets 43 to rotate the work spindles 33 and the workholders 35 to positively rotate the work piece for a grinding operation.e

To attain the primary object of this invention, a control mechanism isprovided which is so arranged as to stop the rotation of the workholders 35 when they are in an upright or predetermined position, thatis, a position in which the work supporting member or surface 31 forms asupport for the work even when the clamping jaws 39 are released so asto prevent the work from dropping out of the machine when it isunclamped. In the preferred construction, as illustrated in thedrawings, this mechanism may comprise an electrical control system whichis so arranged that when it is desired to stop the work rotation, anelectrical apparatus is rendered effective to disengage the clutchmember 55 and to shift the clutch member into a braking position to stopthe work holders in a predetermined position. This control mechanismpreferably comprises a solenoid 89 which is connected by a link 3| withthe yoked member 39. The solenoid 39 is of the pull type and arranged,when energized, to rock the yoked member 39 to move the clutch member 55toward the right, as viewed in Figs. 1 and 2, into engagement with abrake member 53.

In order to energize the solenoid 39 at the proper time, a limit switch33 is provided in an electrical circuit. Power for the electricalcircuit has been illustrated by the power lines 32 which are connectedin series with the limit switch 33 and the solenoid 39 so as to energizethe solenoid 39 at the desired time. The limit switch 33 is preferablymounted on the work head 39, and its plunger 99 is arranged in the pathof a plunger 9| on a bell crank lever 92 which is pivotally mounted on astud 93. During the grinding, when the work holders 33 are rotated, the

limit switch is held open. This is accomplished by means of a chain 95which is connected to the lower end of an arm 05 of bell crank 02. Thechain 95 is in turn connected to a bell crank lever 91, the other arm ofwhich is connected by a. link with the control lever 10. It will bereadily apparent from the disclosure in Fig. 1 that when the controllever I0 is swung toward the left, as viewed in Fig. l, the bell crank01 will be rocked in a clockwise direction to move the bell crank 92also in a clockwise direction so that the pin 9i engages the limitswitch plunger 00, to hold the limit switch in a. normally openposition.

A cam actuated control device is provided to stop the work holder 35in'the desired and predetermined position, namely, a position in whichthe supporting member 31 will serve as a support for the work piece orcrankshaft even when the same has been unclamped. This mechanism maycomprise a cam I02 which is adjustably mounted on one of the work heads35. The cam is provided with elongated slots and clamping screws so thatthe position of the cam may be adjusted relative to the work holder 35.A cam follower roller I8 is mounted on a stud I09 on an arm I ID of thebell crank lever 92. A spring I03 tends to hold the roller I08 inengagementwith cam I02.

The operation of the mechanism is readily apparent from the foregoingdisclosure. The opof the work holder in the desired position. After thecam I02 has been once adjusted, the cam may be locked in adjustedposition so that on successive grinding operations, the work holder isalways stopped in the same predetermined or upright position withoutattention on the part of the operator.

To start the work rotating after loading a. new piece of work into themachine, the operator moves the control lever 10 in a counterclockwisedirection (Fig. 1) into a full line position, as indicated in Fig. 2.This movement of the control lever 10 serves to throw the clutch member55 into engagement with the positively rotated clutch member 56 torotate the work supporting head 35. At the same time the control leveris moved in a counterclockwise direction, the link 98, bell crank 91,chain 95, serve to rock bell crank lever 92 in a clockwise direction soas to hold the limit switch 88 in an open position during the grindingoperation when the work holder is rotating.

After the grinding operation has been completed and it is desired tostop the work rotation to permit removal of the finish ground piece ofwork, theoperator moves the control lever 10 in a clockwise directioninto the full line position as indicated in Fig. 1. This movement of thecontrol lever serves to move the link 95, bell crank 91, chain 95, topermit the spring I03 to rock the bell crank 92 in a counterclockwisedirection so as to bring the follower roll I00 into operative engagementwith the cam I02. Due to the lost motion between the pin 65 andelongated slot 64,

00 remains open andcontinues to remain open until the head has rotatedthrough a partial rotation'into the position illustrated in Fig. 1, inwhich'the roller I00 engages the notched or low portion of the cam I02,thereby closing the limit 5 switch 00 and to energize the solenoid 00,which serves to move the clutch member 55 from engagement with clutchmember 50 into engagement with the brake member 50 to stop the rotationof the work holder 05 in a predetermined l0 or upright position.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a cylindrical grinding machine, a rdl5 tatable grinding wheel awork support, a work holder rotatably mounted thereon, means to supporta work piece thereon, means to continuously rotate said work holder togrind the periphery of the work piece, and automatically 20 actuatedmeans to stop said work holder in a predetermined position.

2. In a grinding machine, a work support, a work holder rotatablymounted on said support, means including a clutch to continuously rotatesaid work holder, and an automatically actua'ted mechanism actuated intimed relation with said clutch to stop the work holder in apredetermined loading position.

3. In a grinding machine, a work support, a 80 automatically actuatedmeans to stop the rotation of the work holder when the fixed support onthe work holder is in a predetermined position.

4. In a grinding machine, a work support, a 40 work holder rotatablymounted on said support and having a work supporting surface arranged tobe loaded and support the work when in an upright position, a clampingmember opposed to said supporting surface to clamp the work rigid- 45lyon said surface, means including a clutch to rotate said work holder,and automatically actuated means cooperating with said clutch to stopthe work rotation when said surface of the work 7 holder is in anupright position.

5. In a grinding machine, a work support, a work holder rotatablymounted on said support, a work supporting surface on said work holderwhich serves to align and support a work piece thereon, a clamping meanson said work holder 55 arranged to clamp the work piece rigidly in saidsurface, means including a clutch to rotate said work holder, 9, controlcam adjustably mounted on said work holder, and a control deviceassociated with said clutch and cam to automatically 60 stop therotation of the work holder in a predetermined or upright position.

6. In a grinding machine, a work support, a work holder rotatablymounted on said support.

a fixed member on said work holder arranged to 65 support and align awork piece thereon, a clamping means to clamp a work piece on said fixedmember. means to rotate said work holder, and an electrically actuatedcam controlled means to automatically stop the rotation of the workhold- 7 er in a predetermined position. I

'7.'In a grinding machine, a work support, a workholder rotatablymounted on said support,

' a'fixe'd member on said holder arranged to support and align a workpiece thereon, a clamping T5 means arranged to clamp a work piecerigidly in said nxed member, means including a clutch to rotate saidwork holder, and an electrically and align a work piece thereon, aclamping means on said holder arranged to clamp a work piece rigidly inengagement with said fixed member, means including a clutch to rotatesaid work holder, a manually operable means to engage said clutch tostart or stop the rotation of said work holder, an adjustable cammounted on said work holder, a control means associated with said camand rendered eitective when the manual means is moved into a stoppingposition to automatically stop the rotation of the work holder when saidfixed member is in a vertical or upright position.

9.In a grinding machine, a work support, a work holder rotatably mountedon said support, means including a clutch to rotate said work holder,manually operable means .to actuate said clutch to rotate said, workholder, a brake associated with said clutch to stop the rotation of thework holder, an adjustable cam mounted on said work holder, and anelectrical control deis vice including a switch associated with said camand a solenoid arranged to move said clutch into engagement with saidbrake which is rendered eflective when the manual means is moved to astopping position to automatically stop the 10 rotation of the workholder in a predetermined position.

10. In a grinding machine, a work support, a work holder rotatablymounted on said support, means including a clutch to rotate said work 16holder, a manually operable means to engage said clutch to start or stopthe rotation oi! said work holder, a brake associated with said clutchto positively stop the rotation oi the work holder, and an electricallycontrolled, cam actuated 20 mechanism which is rendered eilective toengage the clutch and to automatically engage the brake and stop therotation of the work holder in a predetermined position.

HERBERT A. SILVEN.

